1. Field of the Invention
The present invention relates to an image forming apparatus such as a digital photo printer, a duplicating machine, an electrograph and so on, and more particularly to an image forming apparatus which provides plurality of cassettes (paper feeder) for being set print media.
2. Description of the Related Art
A conventional printer connected to upper apparatus such as a main computer usually includes a plurality of paper cassettes. Print media information, such as different types, sizes or color paper, is saved in the paper cassettes in advance. The conventional printer selects the paper cassette to feed paper according to the print media information transmitted from the upper apparatus and prints on the anticipant print media. If there is no print media in the paper cassettes, the conventional printer automatically switch to select other paper cassettes to feed paper.
As disclosed in Official Gazette of Japanese Patent Application Laid-Open No. 2000-143017, the conventional printer provides plurality of paper feeding trays. If there is no paper in a selected paper feeding tray when feeding paper, the other tray with same paper information (size, kind) of the selected tray is automatically switched to feed paper. In this case, if there is no tray having same paper information with the selected paper feeding tray, print error of the selected tray with no paper is displayed and the print processing is paused. If there is no tray that contains matched paper information with that of the upper apparatus, the printer designates the tray contains inconsistent paper information to feed paper and executes printing forcibly (continue print mode).
However, when the conventional printer performs continue print job, if the print media of the selected paper feeding tray is used up, the paper feeding system will automatically switch to other trays. Because the other trays may be of different paper information with that of the selected paper feeding tray, the print job may be printed on the unexpected print media.